Abstract

The efficient power exchange between waveguides in a directional coupler occurs when the propagation constants of their guided modes are equal. The coupling between nonidentical waveguides can be accomplished with the help of a power dependence of the propagation constant in a nonlinear waveguide. For low energies phase matching of different waveguides modes can be obtained with the help of a grating formed by a periodic perturbations of the refractive index [1,5]. The gratings in so called Grating-Assisted Couplers are usually formed during a fabrication process and have constant, immutable parameters.

© 1993 Optical Society of America